-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hello,
After having a look at the code I am currently trying to test this, but building master seems not to yield a library with SPLASH_CMYK enabled. Are there special configure flags that have to be set or dependencies that have to be fulfilled? Thanks for any help. Best regards, Adam. On 20.10.2012 17:36, Thomas Freitag wrote: > On 16.10.2012 22:57, Albert Astals Cid wrote: >> El Dilluns, 15 d'octubre de 2012, a les 07:15:51, Thomas Freitag >> va escriure: >>> On 14.10.2012 22:58, Albert Astals Cid wrote: >>>> El Diumenge, 14 d'octubre de 2012, a les 19:41:26, Thomas >>>> Freitag va >> escriure: >>>>> On 14.10.2012 17:21, Albert Astals Cid wrote: >>>>>> El Diumenge, 14 d'octubre de 2012, a les 13:47:29, Thomas >>>>>> Freitag va >>>> escriure: >>>>>>> Hi folks! >>>>>>> >>>>>>> Is there anybody in the community who wants the >>>>>>> possibility to simulate overprint in qt library? With >>>>>>> the implementation of DeviceN support in splash this >>>>>>> is quite easy now, so I can upload a patch. >>>>>> Sure, why not? Let's see the patch :-) >>>>> Okay, here it is. >>>> The two new methods are missing @since markers (and also i >>>> think the documentation of the two methods could be a bit >>>> more explanatory) >>> @since: I thought that You insert it when You commit it. If I >>> would insert 0.22.0 You have to change it if You will not have >>> the time to commit it :-) or I need to change it and have to >>> upload a new patch if You will not have the time :-( >> Well, if you do it, it's less work i have to do and thus it's >> easier i'll have time ;-) > Because I removed these two new methods now there is no need to > comment them anymore :-) But I introduced a new (static) method > "okToUseOverprint" which just proofs if poppler is compiled with > SPLASH_CMYK, and there I add the @since comment now. >> >>> Explanatory: Okay, but this will be hard. For those who know >>> what overprint is the documentation is self-explanatory, for >>> others I need to write reams. What's about to insert the link >>> to http://en.wikipedia.org/wiki/Overprinting? >> To be honest doesn't seem to make things much clearer to me :D > Okay, let me try to explain it in my own words: First of all, in > the normal behaviour, if something is painted everything previously > painted at this place is knocked out. This is rather simplified, > because we ignore functionality like transparency, blending modes > etc. Now let us have a look at the printing process with 4 > different colour plates Cyan, Magenta, Yellow and Black. Without > setting the overprint mode, the behaviour is the same: if > something is painted everything previously painted on every plate > is knocked out. But when overprint mode is enabled, and i.e. in a > DeviceN colorspace with only one process colour, let us assume > Cyan, the Magenta, Yellow and Black plates kept untouched and only > previously painted objects on the Cyan plate at this position are > knocked out. But when You paint in DeviceCMYK, the behaviour > remains the same (all is knocked out) even with overprint on, > unless You set overprint mode to true in addition. With overprint > mode true You need to look at the colour components You use for > painting: if the a component is 0 the corresponding colour plate is > left untouched again, if it is not 0 it will be knocked out again > on this colour plate. If there is a additional spot colour plate, > it is similar: overprint false: everything is knocked out, > overprint true: if You paint with process colours only this spot > colour plate is left untouched, if You paint with this spot colour, > the process colour plates remain untouched but on this spot colour > plate previously painted objects are knocked out. As I said, this > is rather simplified, there are special rules for images, blending > modes and so on and so on. A complete explanation can be found in > the PDF specification. As overprint just works on colour plates, > You'll see no effects when You print in RGB as on a monitor, > therefore You have to simulate the effects (overprint preview :-) ) > if You want to see them on a monitor. >> Ok, let's leave the docu as it is >> >>>> Also why are you calling it "overprint preview"? How is it a >>>> preview? >>> To be honest, I haven't really thought about that. Probably I >>> choose that name because it is also introduced in GlobalParams >>> with that name. But also in the acrobat reader preferences it >>> is called "Use overprint preview". And because not all RIPs >>> support it (i.e. RGB printers) it is indeed something like a >>> preview (for RIPs which support it). >> Ok, let's leave it with that name (but maybe make it a >> RenderingHint as Adam suggests?). > I tried to understand what You meant with RenderingHint and made > it, hopefully it is what You meant. I attach the changed patches > (poppler and okular). > > Cheers, Thomas >> >> Cheers, Albert >> >>>> Given that overprint only works if defined(SPLASH_CMYK) you >>>> should make the setter return a boolean that says if the set >>>> worked or not (i.e. make it fail if !defined(SPLASH_CMYK)) >>> Gotcha. I thought about that and disable / enable the option in >>> okular if the format generator doesn't support it. But because >>> I'm not familiar enough with okular I defered it and then >>> forgot it... I'll insert it in QT when I get answers to the >>> other points. >>> >>> Cheers, Thomas >>> >>>> Cheers, >>>> >>>> Albert >>>>> In a few places it has already a similar implementation >>>>> than in bug 50992 (thread safe), because changing the >>>>> overprint option also meant that we need a different >>>>> SplashOutputDev instance. But You probably also want to >>>>> test it in okular? Even if we are here not on an okular >>>>> list, I attach the okular patch here, too. Also here, it >>>>> has already the changes from bug 50992. But because >>>>> POPPLER_QT_THREADSAFE is not defined here, it doesn't make >>>>> any difference, so I let these changes as they are. BTW, >>>>> I'm not really familiar with qt programming, so most >>>>> changes in okular are more or less a (hopefully) best >>>>> guess. >>>>> >>>>> Cheers, Thomas >>>>> >>>>>> Cheers, >>>>>> >>>>>> Albert >>>>>>> For everybody who doesn't know anything about overprint >>>>>>> I attach three screenshots which shows the >>>>>>> implementation in okular. (This is not fake, I made a >>>>>>> small apprentice piece today morning :-) ) >>>>>>> >>>>>>> Cheers, Thomas >>>>>> _______________________________________________ poppler >>>>>> mailing list [email protected] >>>>>> http://lists.freedesktop.org/mailman/listinfo/poppler >>>>>> >>>>>> . >>>> _______________________________________________ poppler >>>> mailing list [email protected] >>>> http://lists.freedesktop.org/mailman/listinfo/poppler >>>> >>>> . >>> _______________________________________________ poppler mailing >>> list [email protected] >>> http://lists.freedesktop.org/mailman/listinfo/poppler >> _______________________________________________ poppler mailing >> list [email protected] >> http://lists.freedesktop.org/mailman/listinfo/poppler >> >> . >> > > > > _______________________________________________ poppler mailing > list [email protected] > http://lists.freedesktop.org/mailman/listinfo/poppler > -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://www.enigmail.net/ iQEcBAEBAgAGBQJQhCpLAAoJEPSSjE3STU3444UH/jLLVd/SXnKKr0gMUAwm3hBl 53xLJ+5t0ST5OU5EoXf2NoHWQmotOwoFolM2UJ7NAKROpWAq73SHjgy+dGY0UVam S2GECoPnTi9Q7ggpsRB0mktmxyYnEe9TQDL3/XILA6+OKQpVRskZgJa7Io3B1sj7 9XjIMlB1QLDGZFQFVcLLErkao85lUpiZra1t14XBQb8UGTbVoSy/q7jszUENPA4J lWliUCVpb3kskkEp+AUyvaGIpCsQTAGuZc/3OIzySpamKX93y3S+YVJ4hqN8AcDk o2KkceUVWd55cmU2lYLzz7TTiSAs9l0fP1XH33K06arXlREUMG54s3ekDvyaKKg= =n1/o -----END PGP SIGNATURE----- _______________________________________________ poppler mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/poppler
